"""A generic class to build line-oriented command interpreters.Interpreters constructed with this class obey the following conventions:1. End of file on input is processed as the command 'EOF'.2. A command is parsed out of each line by collecting the prefix composed of characters in the identchars member.3. A command `foo' is dispatched to a method 'do_foo()'; the do_ method is passed a single argument consisting of the remainder of the line.4. Typing an empty line repeats the last command. (Actually, it calls the method `emptyline', which may be overridden in a subclass.)5. There is a predefined `help' method. Given an argument `topic', it calls the command `help_topic'. With no arguments, it lists all topics with defined help_ functions, broken into up to three topics; documented commands, miscellaneous help topics, and undocumented commands.6. The command '?' is a synonym for `help'. The command '!' is a synonym for `shell', if a do_shell method exists.7. If completion is enabled, completing commands will be done automatically, and completing of commands args is done by calling complete_foo() with arguments text, line, begidx, endidx. text is string we are matching against, all returned matches must begin with it. line is the current input line (lstripped), begidx and endidx are the beginning and end indexes of the text being matched, which could be used to provide different completion depending upon which position the argument is in.The `default' method may be overridden to intercept commands for which thereis no do_ method.The `completedefault' method may be overridden to intercept completions forcommands that have no complete_ method.The data member `self.ruler' sets the character used to draw separator linesin the help messages. If empty, no ruler line is drawn. It defaults to "=".If the value of `self.intro' is nonempty when the cmdloop method is called,it is printed out on interpreter startup. This value may be overriddenvia an optional argument to the cmdloop() method.The data members `self.doc_header', `self.misc_header', and`self.undoc_header' set the headers used for the help function'slistings of documented functions, miscellaneous topics, and undocumentedfunctions respectively.These interpreters use raw_input; thus, if the readline module is loaded,they automatically support Emacs-like command history and editing features."""importstring,sys__all__=["Cmd"]PROMPT='(Cmd) 'IDENTCHARS=string.ascii_letters+string.digits+'_'classCmd:"""A simple framework for writing line-oriented command interpreters. These are often useful for test harnesses, administrative tools, and prototypes that will later be wrapped in a more sophisticated interface. A Cmd instance or subclass instance is a line-oriented interpreter framework. There is no good reason to instantiate Cmd itself; rather, it's useful as a superclass of an interpreter class you define yourself in order to inherit Cmd's methods and encapsulate action methods. """prompt=PROMPTidentchars=IDENTCHARSruler='='lastcmd=''cmdqueue=[]intro=Nonedoc_leader=""doc_header="Documented commands (type help <topic>):"misc_header="Miscellaneous help topics:"undoc_header="Undocumented commands:"nohelp="*** No help on %s"use_rawinput=1def__init__(self,completekey='tab'):"""Instantiate a line-oriented interpreter framework. The optional argument is the readline name of a completion key; it defaults to the Tab key. If completekey is not None and the readline module is available, command completion is done automatically. """ifcompletekey:try:importreadlinereadline.set_completer(self.complete)readline.parse_and_bind(completekey+": complete")exceptImportError:passdefcmdloop(self,intro=None):"""Repeatedly issue a prompt, accept input, parse an initial prefix off the received input, and dispatch to action methods, passing them the remainder of the line as argument. """self.preloop()ifintroisnotNone:self.intro=introifself.intro:printself.introstop=Nonewhilenotstop:ifself.cmdqueue:line=self.cmdqueue[0]delself.cmdqueue[0]else:ifself.use_rawinput:try:line=raw_input(self.prompt)exceptEOFError:line='EOF'else:sys.stdout.write(self.prompt)sys.stdout.flush()line=sys.stdin.readline()ifnotlen(line):line='EOF'else:line=line[:-1]# chop \nline=self.precmd(line)stop=self.onecmd(line)stop=self.postcmd(stop,line)self.postloop()defprecmd(self,line):"""Hook method executed just before the command line is interpreted, but after the input prompt is generated and issued. """returnlinedefpostcmd(self,stop,line):"""Hook method executed just after a command dispatch is finished."""returnstopdefpreloop(self):"""Hook method executed once when the cmdloop() method is called."""passdefpostloop(self):"""Hook method executed once when the cmdloop() method is about to return. """passdefparseline(self,line):line=line.strip()ifnotline:returnNone,None,lineelifline[0]=='?':line='help '+line[1:]elifline[0]=='!':ifhasattr(self,'do_shell'):line='shell '+line[1:]else:returnNone,None,linei,n=0,len(line)whilei<nandline[i]inself.identchars:i=i+1cmd,arg=line[:i],line[i:].strip()returncmd,arg,linedefonecmd(self,line):"""Interpret the argument as though it had been typed in response to the prompt. This may be overridden, but should not normally need to be; see the precmd() and postcmd() methods for useful execution hooks. The return value is a flag indicating whether interpretation of commands by the interpreter should stop. """cmd,arg,line=self.parseline(line)ifnotline:returnself.emptyline()ifcmdisNone:returnself.default(line)self.lastcmd=lineifcmd=='':returnself.default(line)else:try:func=getattr(self,'do_'+cmd)exceptAttributeError:returnself.default(line)returnfunc(arg)defemptyline(self):"""Called when an empty line is entered in response to the prompt. If this method is not overridden, it repeats the last nonempty command entered. """ifself.lastcmd:returnself.onecmd(self.lastcmd)defdefault(self,line):"""Called on an input line when the command prefix is not recognized. If this method is not overridden, it prints an error message and returns. """print'*** Unknown syntax:',linedefcompletedefault(self,*ignored):"""Method called to complete an input line when no command-specific complete_*() method is available. By default, it returns an empty list. """return[]defcompletenames(self,text,*ignored):dotext='do_'+textreturn[a[3:]forainself.get_names()ifa.startswith(dotext)]defcomplete(self,text,state):"""Return the next possible completion for 'text'. If a command has not been entered, then complete against command list. Otherwise try to call complete_<command> to get list of completions. """ifstate==0:importreadlineorigline=readline.get_line_buffer()line=origline.lstrip()stripped=len(origline)-len(line)begidx=readline.get_begidx()-strippedendidx=readline.get_endidx()-strippedifbegidx>0:cmd,args,foo=self.parseline(line)ifcmd=='':compfunc=self.completedefaultelse:try:compfunc=getattr(self,'complete_'+cmd)exceptAttributeError:compfunc=self.completedefaultelse:compfunc=self.completenamesself.completion_matches=compfunc(text,line,begidx,endidx)try:returnself.completion_matches[state]exceptIndexError:returnNonedefget_names(self):# Inheritance says we have to look in class and# base classes; order is not important.names=[]classes=[self.__class__]whileclasses:aclass=classes[0]ifaclass.__bases__:classes=classes+list(aclass.__bases__)names=names+dir(aclass)delclasses[0]returnnamesdefcomplete_help(self,*args):returnself.completenames(*args)defdo_help(self,arg):ifarg:# XXX check arg syntaxtry:func=getattr(self,'help_'+arg)except:try:doc=getattr(self,'do_'+arg).__doc__ifdoc:printdocreturnexcept:passprintself.nohelp%(arg,)returnfunc()else:names=self.get_names()cmds_doc=[]cmds_undoc=[]help={}fornameinnames:ifname[:5]=='help_':help[name[5:]]=1names.sort()# There can be duplicates if routines overriddenprevname=''fornameinnames:ifname[:3]=='do_':ifname==prevname:continueprevname=namecmd=name[3:]ifhelp.has_key(cmd):cmds_doc.append(cmd)delhelp[cmd]elifgetattr(self,name).__doc__:cmds_doc.append(cmd)else:cmds_undoc.append(cmd)printself.doc_leaderself.print_topics(self.doc_header,cmds_doc,15,80)self.print_topics(self.misc_header,help.keys(),15,80)self.print_topics(self.undoc_header,cmds_undoc,15,80)defprint_topics(self,header,cmds,cmdlen,maxcol):ifcmds:printheaderifself.ruler:printself.ruler*len(header)(cmds_per_line,junk)=divmod(maxcol,cmdlen)col=cmds_per_lineforcmdincmds:ifcol==0:printprint(("%-"+`cmdlen`+"s")%cmd),col=(col+1)%cmds_per_lineprint"\n"